public class Computer{
    public void powerOn(){
        System.out.println("开机");
    }
    public void powerOff(){
        System.out.println("关机");
    }

    public void useDevice(USB usb){
        usb.openDevice();
        if (usb instanceof Mouse){
            Mouse mouse = (Mouse) usb;
            mouse.click();
        }else if (usb instanceof Keybroad){
            Keybroad keybroad = (Keybroad) usb;
            keybroad.inPut();
        }
        usb.closeDevice();
    }
}
